Indoor farm finds hurdles with aquaponics systems

In the depth of the Chicago winter, it’s hard to find any signs of life. On a Saturday in the middle of February, grey skies and the temperatures in the upper 30s only brought cold rain.

This weather couldn’t touch the flourishing life inside The Plant, a large brick complex just south of Chicago. In their basement a whole floor was alive with fresh produce you might see at an April farmer’s market—lettuce, kale, swiss chard.

Jonathan Pereira, Executive Director of the non-profit Plant Chicago, welcomed visitors to his business’s underground farming operation in a plain grey t-shirt and faded jeans, illuminated by bright purple lights that served as sunlight for the plants.

“This farm is really meant to be open to the public,” Pereira said. “Commercial growers don’t necessarily want people coming in their space all the time. It’s distracting. You could bring in pathogens.”

Pereira laughed a little—"we just let that come in.”

In the basement of the building there are roughly 300 square feet of farming happening without soil and without sunlight.

But plants aren’t the only living things in the basement. At the back of the room are two large blue tubs filled with fish—usually tilapia or perch. Plant Chicago’s farming system, called an aquaponics system, harnesses the relationship of fish and plants to provide natural fertilizers for the plants.

The purpose of Plant Chicago, in Pereira’s words, is to “cultivate local, circular economies.” An aquaponics system, boiled down, is just that.

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The aquaponics system at The Plant features a variety of greens, from lettuce to aloe plants to a small jasmine tree in the middle of the room.

In large blue tubs in the back of the room are fish who are making their contributions to the growing plants—via their poop.

If you came down to The Plant on a given Saturday and asked Pereira to explain the aquaponics system to you, he can make it seem pretty simple:

“You have fish in water,” Pereira said. “They have outputs: liquids and solids.”

From there it gets a little more complicated. This output from the fish (output = poop) is eventually going to be used as a fertilizer. In its immediate form, however, this waste is full of ammonia and not usable by plants as fertilizer. In order to convert the waste into a proper meal for the plants, there has to be a third party involved—bacteria.

Kevin Erickson, Urban Agriculture Coordinator at Loyola University, oversees Loyola’s aquaponics systems. They grow their plants in gravel to help the roots of the plant take hold.

“Bacteria are living in the gravel in this system,” Erickson said. “So as the water passes through bacteria is actually consuming the material.”

When the bacteria consume the ammonia-rich waste, they convert it into nitrite. What Erickson has found is that there are two different strains of bacteria that exist. One converts the ammonia (poop) to nitrite. The other strain converts nitrite to nitrate.

This nitrate is the final form that can be used as a fertilizer for the plants. The fish poop is finally turned into a snack for the growing greens.

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In its purest and most successful form, an aquaponics system is a fully circular system. Fish feeds plant feeds fish. This kind of closed-loop economy has been hailed as a sustainable answer to agriculture. Aquaponics exists at this intersection of “aquaculture,” or raising fish, and “hydroponics,” which is growing plants without soil.

If you’ve ever won a goldfish from a fair or raised guppies as a child, then you know that the old water from the tank goes down the toilet or down the sink. With aquaponics, Erickson says, this nutrient-rich water is used as for the plants.

“Aquaponics was started to basically address sustainability issues with hydroponics,” Erickson said. “[Hydroponics] requires 100% inorganic fertilizers that include mined nutrients and minerals, and they’re generally not locally sourced.”

Growing plants through hydroponics can involve growing in gravel, beads or nutrient-rich water. No matter how, though, the fertilizers for the plants are brought in from outside.

While not the most sustainable form of urban growing, hydroponics has its benefits.

“Hydroponics is easier to control,” Jonathon Pereira, back at Plant Chicago, says. “You’re controlling inputs—you put in your nutrient mix into the water, whereas with aquaponics you’re feeding the fish and relying on their outputs to be the fertilizer source.”

Pereira has seen how the variability of aquaponics systems limits their growth.

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While aquaponics is sustainable, it is not always profitable. The aquaponics farm in the basement of The Plant was actually meant to be a large-scale farming operation.

“If you read the really really old newspaper clippings from back in the day, they talked about how this building was supposed to be entirely a vertical farm,” Eric Weber, Technology Coordinator at Plant Chicago, said. “So aquaponics was basically supposed to take over the entire place.”

Aquaponics turned out to be difficult for meeting profit margins. Farming outside is already incredibly labor intensive—"high overhead, low return”—as Weber described it. Take farming and put it in a Chicago building with high rent and the numbers just don’t seem to work out.

It’s not just the cost of rent in Chicago that makes running an aquaponics farm hard. Pereira explained that you have to closely monitor each system to make sure that the cycle is balanced.

“If it becomes off-balance, the fish will die first before the plants,” Pereira said. “There’s different levels of bacteria that can harm the fish that you wouldn’t be dealing with in the plant. There’s more variables in the system to fail.”

Erickson, over at the Loyola aquaponics system, has experienced his own problem with profitability.

“I haven’t been able to produce fish and sell them in a way that makes the fish profitable,” Erickson said. “The fish are really there to generate fertility for the plants.”

The plants, he explains, are what end up being the profitable part of any aquaponics system. But in order for the plants to be profitable, they need to be “quick turnover, highly marketable plants” that can go straight out the door and into the local market.

There also needs to be a large operation going on in order to turn a profit, Erickson explained. Large-scale operations are more fruitful, pun intended. Growing more produce “allows for energy and infrastructure expenses to see a return on investment.”

As a result of these difficulties, Plant Chicago ended up switching from the business side of aquaponics to the education side of it.

“Over time we ended up scaling back the aquaponics systems,” Weber said. “So as you see them today, they’re much more designed around the sense of demonstrating what the concept of the circular economy is.”

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It may be that Chicago needs a demonstrational aquaponics farm more than it needs a productive one. Pereira said that, in 2018, Plant Chicago did workshops with over 3,600 Chicago youth.

“Youth programming is in really high demand in this part of the city,” Pereira said. “There really isn’t a whole lot of opportunity for informal science education.”

So Plant Chicago is doing just that—bringing youth in from around the city. They have a students from South Side Occupational that come every Friday on a work study program. While at the aquaponics farm they learn to transplant, grow, harvest, clean and do other work to help grow produce.

Plant Chicago also works with adults, teaching them the basic concepts of preserving or composting.

Their aquaponics farm that lives in the basement is one way to teach students of all ages about closed-loop systems.

Weber said that the aquaponics system is a good way to introduce the concept of a circular economy. Kids don’t necessarily understand the industrial production system or Western capitalist society, Weber explained, but aquaponics is a good start.

“It’s really easy to explain to them: Fish poop, bacteria eat poop, bacteria provide food for plants, we eat plants,” Weber said. “That form of circularity is very easy to grasp for kids.”

“There’s a very large impact we can make,” Weber said. “Finding as many ways as possible to get people to grow their own food, or at least be conscious of where their food actually comes from, they that they can make better decisions regarding where they purchase their food.”